The present research of cold-beating formation mainly focused on roller design and manufacture, kinematics, constitutive relation, metal flow law, thermo-mechanical coupling, surface micro-topography and microstructur...The present research of cold-beating formation mainly focused on roller design and manufacture, kinematics, constitutive relation, metal flow law, thermo-mechanical coupling, surface micro-topography and microstructure evolution. However, the research on surface quality and performance of workpieces in the process of cold-beating is rare. Cold-beating simulation experiment of 1020 steel is conducted at room temperature and strain rates ranging from 2000 to 4000 s^-1 base on the law of plastic forming. According to the experimental data, the model of strain hardening of 1020 steel is established, Scanning Electron Microscopy（SEM） is conducted, the mechanism of the work hardening of 1020 steel is clarified by analyzing microstructure variation of 1020 steel. It is found that the strain rate hardening effect of 1020 steel is stronger than the softening effect induced by increasing temperatures, the process of simulation cold-beating cause the grain shape of 1020 steel significant change and microstructure elongate significantly to form a fibrous tis- sue parallel to the direction of deformation, the higher strain rate, the more obvious grain refinement and the more hardening effect. Additionally, the change law of the work hardening rate is investigated, the relationship between dislocation density and strain, the relationship between work hardening rate and dislocation density is obtained. Results show that the change trend of the work hardening rate of 1020 steel is divided into two stages, the work hardening rate decreases dramatically in the first stage and slowly decreases in the second stage, finally tending toward zero. Dislocation density increases with increasing strain and strain rate, work hardening rate decreases with increasing dislocation density. The research results provide the basis for solving the problem of improving the surface quality and performance of workpieces under cold-beating formation of 1020 steel.展开更多
To improve the separation capacity of uranium in aqueous solutions, 3R-MoS2 nanosheets were prepared with molten salt electro- lysis and further modified with polypyrrole (PPy) to synthesize a hybrid nanoadsorbent (PP...To improve the separation capacity of uranium in aqueous solutions, 3R-MoS2 nanosheets were prepared with molten salt electro- lysis and further modified with polypyrrole (PPy) to synthesize a hybrid nanoadsorbent (PPy/3R-MoS2). The preparation conditions of PPy/3R- MoS2 were investigated and the obtained nanosheets were characterized with scanning electron microscope (SEM), high resolution transmis- sion electron microscope (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectro- scopy (XPS). The results showed that PPy/3R-MoS2 exhibited enhanced adsorption capacity toward U(VI) compared to pure 3R-MoS2 and PPy;the maximum adsorption was 200.4 mg/g. The adsorption mechanism was elucidated with XPS and FTIR: (1) negatively charged PPy/3R-MoS2 nanosheets attracted by an electrostatic interaction;(2) exposed C, N, Mo, and S atoms complexed with U(VI) through co- ordination;(3) Mo in the complex partly reduced the adsorbed U(VI) to U(IV), which further regenerated the adsorption point and continu- ously adsorbed U(VI). The design of the PPy/3R-MoS2 composite with a high adsorption capacity and chemical stability provides a new direc- tion for the removal of radionuclide.展开更多
Objective In this study, we evaluated the difference of progression-free survival(PFS) and overall survival(OS) between extensive-stage small-cell lung cancer(ES-SCLC) patients who acquired partial response(PR) or com...Objective In this study, we evaluated the difference of progression-free survival(PFS) and overall survival(OS) between extensive-stage small-cell lung cancer(ES-SCLC) patients who acquired partial response(PR) or complete remission(CR) after two cycles of first-line chemotherapy with the etoposide plus cisplatin(EP) regimen and those who acquired PR or CR after four or six cycles.Methods A total of 106 eligible patients treated with the EP chemotherapy regimen for two to six cycles, at The General Hospital of Shenyang Military Region(China) between November 2004 and May 2011, were enrolled in this study. RECIST version 1.1 was used for the evaluation of chemotherapy efficiency. We followed up all eligible patients every 4 weeks. All statistical data were analyzed by using SPSS 21.0 statistical package for Windows.Results After a median follow-up of 293 days(range, 62–1531 days), all patients had died by the cutoff date. Fifty-one patients acquired PR or CR after two cycles of chemotherapy; the median PFS reached 6.0 months(95% CI, 5.1–6.9), and the median OS was 10.5 months(95% CI, 8.6–12.4). Twenty-eight patients acquired PR or CR after four or six cycles; the median PFS was 4.8 months(95% CI, 4.4–5.2), and the median OS was 7.5 months(95% CI, 6.8–8.2). Both PFS and OS showed a statistical difference between the two groups. Conclusion ES-SCLC patients who acquired PR or CR after two cycles of the EP regimen as first-line therapy had longer PFS and OS than those who acquired PR or CR after four or six cycles.展开更多
With the increasing size of space facilities,on-orbit assembly requires robots to move on different heights of trusses.This paper proposes a bio-inspired attachment mechanism for robot feet to enable climbing on diffe...With the increasing size of space facilities,on-orbit assembly requires robots to move on different heights of trusses.This paper proposes a bio-inspired attachment mechanism for robot feet to enable climbing on different heights of trusses.Inspired by the attachment and grasping abilities of Dynastes Hercules,we utilize its foot microstructures,such as microhooks and setae,to achieve efficient contact and firm grip with the surface.The morphology and arrangement of these structures can inspire the design of robot feet to improve their grasping and stability performance.We study the biological structure of Dynastes Hercules,design and optimize the bio-inspired structure,analyze the influence of various factors from theoretical and experimental perspectives,and verify the feasibility of the scheme through simulation.We propose an ideal climbing strategy that provides useful reference for robot applications in practice.Moreover,the influence laws of various factors in this paper can be applied to robot foot design to improve their operation ability and stability performance in the space environment.This bio-inspired mechanism can improve robot working range and efficiency,which is critical for on-orbit assemblyin space.展开更多
We proposed absorbing interface conditions for the simulation of linear wave propagation on non-uniform meshes.Based on the superposition principle of second-order linear wave equations,we decompose the interface cond...We proposed absorbing interface conditions for the simulation of linear wave propagation on non-uniform meshes.Based on the superposition principle of second-order linear wave equations,we decompose the interface condition problem into two subproblems around the interface:for the first one the conventional artificial absorbing boundary conditions is applied,while for the second one,the local analytic solutions can be derived.The proposed interface conditions permit a two-way transmission of low-frequency waves across mesh interfaces which can be supported by both coarse and fine meshes,and perform a one-way absorption of high-frequency waves which can only be supported by fine meshes when they travel from fine mesh regions to coarse ones.Numerical examples are presented to illustrate the efficiency of the proposed absorbing interface conditions.展开更多
Reasonably regulating electronic coupling to promote charge transfer and exciton separation has been regarded a promising approach in catalysis.The material engineering of van der Waals heterojunction(vdWsH)based on t...Reasonably regulating electronic coupling to promote charge transfer and exciton separation has been regarded a promising approach in catalysis.The material engineering of van der Waals heterojunction(vdWsH)based on two-dimensional(2D)materials would be a potential way to optimize the as-prepared extrinsic physicochemical characteristics.However,it was still an almost uncultivated land waiting for exploration in catalysis.Herein,we introduced the inert h-boron nitride(h-BN)in non-metal reduced graphene oxide(GN)catalysts and constructed BN-GN vdWsH.The theoretical calculation demonstrated that the h-BN can effectively modify the electronic properties of graphene.With the introduction of h-BN,the BN-GN vdWsH can obviously enhance the catalytic activity of Li-CO_(2) battery.The existence of BN-GN vdWsH can reduce the overpotential more than 700 mV compared with reduced graphene oxide during the CO_(2) reduction reaction(CO_(2)RR)and CO_(2) evolution reaction(CO_(2)ER),and it extended cyclic stability more than three times,which was one structure design made it work as a high efficient electrocatalyst,catalytic materials.展开更多
In this work,we proposed a new U(Ⅵ)removal strategy combining adsorption and photocatalytic reduction by the PMo_(12)/UiO-66 heterojunctions.The PMo_(12)has been encapsulated in the cavities of Ui O-66 by a one-step ...In this work,we proposed a new U(Ⅵ)removal strategy combining adsorption and photocatalytic reduction by the PMo_(12)/UiO-66 heterojunctions.The PMo_(12)has been encapsulated in the cavities of Ui O-66 by a one-step hydrothermal method,and the PMo_(12)/UiO-66 exhibited high adsorption capacity and photocatalytic activity.The maximal theoretical sorption capacity of U(Ⅵ)on 15%PMo_(12)/UiO-66 reached225.36 mg/g and the photoreduction rate of 15%PMo_(12)/UiO-66 is about thirty times as much as UiO-66.Under the light irradiation,the photogenerated electrons rapidly transport from UiO-66 to PMo_(12),and the photo-generated electrons could efficiently reduce the pre-enriched U(Ⅵ)to U(IV).This work provides new insights into remediation of the radioactive environment.展开更多
Background:Early allograft dysfunction(EAD)is associated with decreased graft and patient survival rates.This study aimed to identify the severity of EAD and develop a predictive model for EAD after donation after cir...Background:Early allograft dysfunction(EAD)is associated with decreased graft and patient survival rates.This study aimed to identify the severity of EAD and develop a predictive model for EAD after donation after circulatory death(DCD)liver transplantation(LT).Furthermore,the influence of operative time on EAD incidence was also evaluated.Methods:In this retrospective,multicentre cohort study,nomograms were established based on a single-centre training cohort(n=321)and validated in a 3-center validation cohort(n=501).Results:The incidence rate of EAD was 46.4%(149/321)in the training cohort and 40.5%(203/501)in the validation cohort.Of the 149 EAD patients in the training cohort,77 patients with either elevated alanine aminotransferase(ALT)or aspartate aminotransferase(AST)were classified as having EAD type A,and the rest of the EAD patients were classified as having EAD type B.Recipients with EAD type B had lower graft and patient survival rates than recipients with EAD type A(P=0.043 and 0.044,respectively).We further developed a nomogram to predict EAD(graft weight,cold ischemia time,donor age,model for end-stage liver disease(MELD)score)and another nomogram to predict EAD type B(graft weight,cold ischemia time,MELD score).The nomograms for the prediction of EAD and EAD type B had good discrimination[concordance index(C-index)=0.712(0.666-0.758),0.707(0.641-0.773)]and calibration[Hosmer-Lemeshow(HL)P=0.384,P=0.425]in the validation cohort.An increased operative time(>6 h)was associated with increased EAD and EAD type B incidence in the high-risk group(P=0.005,P=0.020,respectively).Conclusions:EAD type B was associated with decreased graft and patient survival rates.The novel nomograms effectively predicted the incidence of EAD and EAD type B in DCD LT patients.展开更多
Cadmium (Cd) pollution in agricultural soils has become a severe threat to food security and human health in recent years. Stable Cd isotopes are a potentially powerful tool for identifying the sources of Cd in soils....Cadmium (Cd) pollution in agricultural soils has become a severe threat to food security and human health in recent years. Stable Cd isotopes are a potentially powerful tool for identifying the sources of Cd in soils. However, many Earth surface processes, including adsorption, leaching, and biogeochemical cycles in plants, may generate Cd isotope fractionation, which can complicate the potential application of Cd isotopes in tracing the sources of Cd pollution in soils. In this work, the Cd isotope compositions of typical Fe-Mn nodules (FMNs) and surrounding soils in two different soil profiles are investigated. Our results show that the FMNs in lower layers (i.e., C and W horizons) are isotopically lighter than the surrounding soils by –0.114‰ to –0.156‰ (Δ114/110CdFMN-soil). We interpret this fractionation as the result of preferential adsorption of isotopically light Cd onto the surface of goethite. In the upper layers (i.e., P and A horizons), the Δ114/110CdFMN-soil values are more negative in the P horizon (–0.213‰ to –0.388‰) but more positive in the A horizon (0.061‰ to 0.204‰). We interpret these fractionations as the result of natural biogeochemical processes (i.e., leaching and biological cycling) during soil development. Soil leaching preferentially releases isotopically heavy Cd into the underlying soil (i.e., P horizon), shifting the topsoil towards lower δ114/110Cd values but the underlying soils towards higher δ114/110Cd values. Moreover, biological cycling contributes isotopically heavy Cd to the topsoil, probably shifting the topsoil towards higher δ114/110Cd values. Our study demonstrates that the formation of Fe oxyhydroxides, leaching, and biological cycling can considerably modify the soil Cd isotope signature, highlighting the need to consider natural biogeochemical processes when using Cd isotopes to trace heavy metal pollution in soils.展开更多
The centralized utilization of heavy-metal-contaminated soil has become the main strategy to remediate brownfield-site pollution.However,few studies have evaluated the ecological and human health risks of reusing thes...The centralized utilization of heavy-metal-contaminated soil has become the main strategy to remediate brownfield-site pollution.However,few studies have evaluated the ecological and human health risks of reusing these remediated soils.Considering Zn as the target metal,systematic pHdependent leaching and the Community Bureau of Reference(BCR)extraction were conducted at six pH values(pH=2,4,6,8,10,12)for the remediated soil treated through thermal curing.The pHdependent leaching results showed that with the formation of ZnCr2O4 spinel phases,the remediated soil exhibited strong inherent resistance to acidic attack over longer leaching periods.Furthermore,the BCR extraction results showed that the leaching agent pH value mainly affected the acid-soluble fraction content.Moreover,a strong complementary relationship was noted between the leaching and acid-soluble fraction contents,indicating that the sum of these two parameters is representative of the remediated soil risk value.Therefore,we proposed a two-step calculation method to determine the sum of the two heavy metal parameters as the risk value of remediated soil.In contrast to the traditional one-step calculation method,which only uses the leaching content as the risk value,this two-step calculation method can effectively avoid underestimating the risk of remediated soil.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.551475146,51475366,51075124)
文摘The present research of cold-beating formation mainly focused on roller design and manufacture, kinematics, constitutive relation, metal flow law, thermo-mechanical coupling, surface micro-topography and microstructure evolution. However, the research on surface quality and performance of workpieces in the process of cold-beating is rare. Cold-beating simulation experiment of 1020 steel is conducted at room temperature and strain rates ranging from 2000 to 4000 s^-1 base on the law of plastic forming. According to the experimental data, the model of strain hardening of 1020 steel is established, Scanning Electron Microscopy（SEM） is conducted, the mechanism of the work hardening of 1020 steel is clarified by analyzing microstructure variation of 1020 steel. It is found that the strain rate hardening effect of 1020 steel is stronger than the softening effect induced by increasing temperatures, the process of simulation cold-beating cause the grain shape of 1020 steel significant change and microstructure elongate significantly to form a fibrous tis- sue parallel to the direction of deformation, the higher strain rate, the more obvious grain refinement and the more hardening effect. Additionally, the change law of the work hardening rate is investigated, the relationship between dislocation density and strain, the relationship between work hardening rate and dislocation density is obtained. Results show that the change trend of the work hardening rate of 1020 steel is divided into two stages, the work hardening rate decreases dramatically in the first stage and slowly decreases in the second stage, finally tending toward zero. Dislocation density increases with increasing strain and strain rate, work hardening rate decreases with increasing dislocation density. The research results provide the basis for solving the problem of improving the surface quality and performance of workpieces under cold-beating formation of 1020 steel.
基金the National Nat-ural Science Foundation of China(Nos.21906019,21906018,21561002,21866004,and 21866003)the Sci-ence&Technology Support Program of Jiangxi Province,China(No.2018ACB21007)+1 种基金the Jiangxi Program of Aca-demic and Technical Leaders of Major Disciplines,China(No.20182BCB22011)the Project of the Jiangxi Provincial Department of Education,China(Nos.GJJ160550,GJJ180385,and GJJ180400).
文摘To improve the separation capacity of uranium in aqueous solutions, 3R-MoS2 nanosheets were prepared with molten salt electro- lysis and further modified with polypyrrole (PPy) to synthesize a hybrid nanoadsorbent (PPy/3R-MoS2). The preparation conditions of PPy/3R- MoS2 were investigated and the obtained nanosheets were characterized with scanning electron microscope (SEM), high resolution transmis- sion electron microscope (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectro- scopy (XPS). The results showed that PPy/3R-MoS2 exhibited enhanced adsorption capacity toward U(VI) compared to pure 3R-MoS2 and PPy;the maximum adsorption was 200.4 mg/g. The adsorption mechanism was elucidated with XPS and FTIR: (1) negatively charged PPy/3R-MoS2 nanosheets attracted by an electrostatic interaction;(2) exposed C, N, Mo, and S atoms complexed with U(VI) through co- ordination;(3) Mo in the complex partly reduced the adsorbed U(VI) to U(IV), which further regenerated the adsorption point and continu- ously adsorbed U(VI). The design of the PPy/3R-MoS2 composite with a high adsorption capacity and chemical stability provides a new direc- tion for the removal of radionuclide.
基金Supported by grants from the National Research Key Project of the Twelfth Five-year Plan of the Republic of China(No.2012ZX09303016-002)the Science and Technology Key Programs of Liaoning Province(No.2012225019)
文摘Objective In this study, we evaluated the difference of progression-free survival(PFS) and overall survival(OS) between extensive-stage small-cell lung cancer(ES-SCLC) patients who acquired partial response(PR) or complete remission(CR) after two cycles of first-line chemotherapy with the etoposide plus cisplatin(EP) regimen and those who acquired PR or CR after four or six cycles.Methods A total of 106 eligible patients treated with the EP chemotherapy regimen for two to six cycles, at The General Hospital of Shenyang Military Region(China) between November 2004 and May 2011, were enrolled in this study. RECIST version 1.1 was used for the evaluation of chemotherapy efficiency. We followed up all eligible patients every 4 weeks. All statistical data were analyzed by using SPSS 21.0 statistical package for Windows.Results After a median follow-up of 293 days(range, 62–1531 days), all patients had died by the cutoff date. Fifty-one patients acquired PR or CR after two cycles of chemotherapy; the median PFS reached 6.0 months(95% CI, 5.1–6.9), and the median OS was 10.5 months(95% CI, 8.6–12.4). Twenty-eight patients acquired PR or CR after four or six cycles; the median PFS was 4.8 months(95% CI, 4.4–5.2), and the median OS was 7.5 months(95% CI, 6.8–8.2). Both PFS and OS showed a statistical difference between the two groups. Conclusion ES-SCLC patients who acquired PR or CR after two cycles of the EP regimen as first-line therapy had longer PFS and OS than those who acquired PR or CR after four or six cycles.
基金supported in part by the National Nature Science Foundation of China[No.62073229]Jiangsu Policy Guidance Program(International Science and Technology Cooperation)The Belt and Road Initiative Innovative Cooperation Projects(No.BZ2021016)EDL fund of Beijing Institute of Space Mechanics and Electricity(Grant No.EDL19092127).
文摘With the increasing size of space facilities,on-orbit assembly requires robots to move on different heights of trusses.This paper proposes a bio-inspired attachment mechanism for robot feet to enable climbing on different heights of trusses.Inspired by the attachment and grasping abilities of Dynastes Hercules,we utilize its foot microstructures,such as microhooks and setae,to achieve efficient contact and firm grip with the surface.The morphology and arrangement of these structures can inspire the design of robot feet to improve their grasping and stability performance.We study the biological structure of Dynastes Hercules,design and optimize the bio-inspired structure,analyze the influence of various factors from theoretical and experimental perspectives,and verify the feasibility of the scheme through simulation.We propose an ideal climbing strategy that provides useful reference for robot applications in practice.Moreover,the influence laws of various factors in this paper can be applied to robot foot design to improve their operation ability and stability performance in the space environment.This bio-inspired mechanism can improve robot working range and efficiency,which is critical for on-orbit assemblyin space.
基金supported by the National Key Research and Development Program of China(No.2020YFA0714200)by the National Nature Science Foundation of China(Nos.12125103,12071362)+1 种基金by the Natural Science Foundation of Hubei Province(Nos.2021AAA010,2019CFA007)by the Fundamental Research Funds for the Central Universities.The numerical calculations have been done at the Supercomputing Center of Wuhan University.
文摘We proposed absorbing interface conditions for the simulation of linear wave propagation on non-uniform meshes.Based on the superposition principle of second-order linear wave equations,we decompose the interface condition problem into two subproblems around the interface:for the first one the conventional artificial absorbing boundary conditions is applied,while for the second one,the local analytic solutions can be derived.The proposed interface conditions permit a two-way transmission of low-frequency waves across mesh interfaces which can be supported by both coarse and fine meshes,and perform a one-way absorption of high-frequency waves which can only be supported by fine meshes when they travel from fine mesh regions to coarse ones.Numerical examples are presented to illustrate the efficiency of the proposed absorbing interface conditions.
基金supported by the National Natural Science Foundations of China(Nos:21771024 and 21871028)。
文摘Reasonably regulating electronic coupling to promote charge transfer and exciton separation has been regarded a promising approach in catalysis.The material engineering of van der Waals heterojunction(vdWsH)based on two-dimensional(2D)materials would be a potential way to optimize the as-prepared extrinsic physicochemical characteristics.However,it was still an almost uncultivated land waiting for exploration in catalysis.Herein,we introduced the inert h-boron nitride(h-BN)in non-metal reduced graphene oxide(GN)catalysts and constructed BN-GN vdWsH.The theoretical calculation demonstrated that the h-BN can effectively modify the electronic properties of graphene.With the introduction of h-BN,the BN-GN vdWsH can obviously enhance the catalytic activity of Li-CO_(2) battery.The existence of BN-GN vdWsH can reduce the overpotential more than 700 mV compared with reduced graphene oxide during the CO_(2) reduction reaction(CO_(2)RR)and CO_(2) evolution reaction(CO_(2)ER),and it extended cyclic stability more than three times,which was one structure design made it work as a high efficient electrocatalyst,catalytic materials.
基金financially supported by the National Natural Science Foundation of China(Nos.21866004,21866003,22066003,22076022,22006004)the Defense Industrial Technology Development Program(No.JCKY2019401C004)+2 种基金the Open Fund of Jiangxi Province Key Laboratory of Synthetic Chemistry(No.JXSC202012)the Open Fund of State Key Laboratory of Nuclear Resources and Environment(No.NRE1924)the Graduate Innovation Fund of East China University of Technology(No.DHYC-202134)。
文摘In this work,we proposed a new U(Ⅵ)removal strategy combining adsorption and photocatalytic reduction by the PMo_(12)/UiO-66 heterojunctions.The PMo_(12)has been encapsulated in the cavities of Ui O-66 by a one-step hydrothermal method,and the PMo_(12)/UiO-66 exhibited high adsorption capacity and photocatalytic activity.The maximal theoretical sorption capacity of U(Ⅵ)on 15%PMo_(12)/UiO-66 reached225.36 mg/g and the photoreduction rate of 15%PMo_(12)/UiO-66 is about thirty times as much as UiO-66.Under the light irradiation,the photogenerated electrons rapidly transport from UiO-66 to PMo_(12),and the photo-generated electrons could efficiently reduce the pre-enriched U(Ⅵ)to U(IV).This work provides new insights into remediation of the radioactive environment.
基金supported by grants from the National Science and Technology Major Project(Grant number:2017ZX10203205)National Natural Science Funds for Distinguished Young Scholar of China(Grant number:81625003)+1 种基金Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ17H160006)National Natural Science Foundation of China(Grant number.81570589,81800578).
文摘Background:Early allograft dysfunction(EAD)is associated with decreased graft and patient survival rates.This study aimed to identify the severity of EAD and develop a predictive model for EAD after donation after circulatory death(DCD)liver transplantation(LT).Furthermore,the influence of operative time on EAD incidence was also evaluated.Methods:In this retrospective,multicentre cohort study,nomograms were established based on a single-centre training cohort(n=321)and validated in a 3-center validation cohort(n=501).Results:The incidence rate of EAD was 46.4%(149/321)in the training cohort and 40.5%(203/501)in the validation cohort.Of the 149 EAD patients in the training cohort,77 patients with either elevated alanine aminotransferase(ALT)or aspartate aminotransferase(AST)were classified as having EAD type A,and the rest of the EAD patients were classified as having EAD type B.Recipients with EAD type B had lower graft and patient survival rates than recipients with EAD type A(P=0.043 and 0.044,respectively).We further developed a nomogram to predict EAD(graft weight,cold ischemia time,donor age,model for end-stage liver disease(MELD)score)and another nomogram to predict EAD type B(graft weight,cold ischemia time,MELD score).The nomograms for the prediction of EAD and EAD type B had good discrimination[concordance index(C-index)=0.712(0.666-0.758),0.707(0.641-0.773)]and calibration[Hosmer-Lemeshow(HL)P=0.384,P=0.425]in the validation cohort.An increased operative time(>6 h)was associated with increased EAD and EAD type B incidence in the high-risk group(P=0.005,P=0.020,respectively).Conclusions:EAD type B was associated with decreased graft and patient survival rates.The novel nomograms effectively predicted the incidence of EAD and EAD type B in DCD LT patients.
基金This work was funded by the National Natural Foundation of China(41701266,41977288 and U1612442)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB40020400)+1 种基金the Frontier Science Research Programme(QYZDB-SSW-DQC046)the West Light Foundation of the Chinese Academy of Sciences,and the Science and Technology Foundation of Guizhou Province([2018]1177).
文摘Cadmium (Cd) pollution in agricultural soils has become a severe threat to food security and human health in recent years. Stable Cd isotopes are a potentially powerful tool for identifying the sources of Cd in soils. However, many Earth surface processes, including adsorption, leaching, and biogeochemical cycles in plants, may generate Cd isotope fractionation, which can complicate the potential application of Cd isotopes in tracing the sources of Cd pollution in soils. In this work, the Cd isotope compositions of typical Fe-Mn nodules (FMNs) and surrounding soils in two different soil profiles are investigated. Our results show that the FMNs in lower layers (i.e., C and W horizons) are isotopically lighter than the surrounding soils by –0.114‰ to –0.156‰ (Δ114/110CdFMN-soil). We interpret this fractionation as the result of preferential adsorption of isotopically light Cd onto the surface of goethite. In the upper layers (i.e., P and A horizons), the Δ114/110CdFMN-soil values are more negative in the P horizon (–0.213‰ to –0.388‰) but more positive in the A horizon (0.061‰ to 0.204‰). We interpret these fractionations as the result of natural biogeochemical processes (i.e., leaching and biological cycling) during soil development. Soil leaching preferentially releases isotopically heavy Cd into the underlying soil (i.e., P horizon), shifting the topsoil towards lower δ114/110Cd values but the underlying soils towards higher δ114/110Cd values. Moreover, biological cycling contributes isotopically heavy Cd to the topsoil, probably shifting the topsoil towards higher δ114/110Cd values. Our study demonstrates that the formation of Fe oxyhydroxides, leaching, and biological cycling can considerably modify the soil Cd isotope signature, highlighting the need to consider natural biogeochemical processes when using Cd isotopes to trace heavy metal pollution in soils.
基金the National Key Research and Development Program of China(2018YFC-1801402)GDAS’Project of Science and Technology Development(2020GDASYL-20200103083 and 2020GDASYL-20200301003).
文摘The centralized utilization of heavy-metal-contaminated soil has become the main strategy to remediate brownfield-site pollution.However,few studies have evaluated the ecological and human health risks of reusing these remediated soils.Considering Zn as the target metal,systematic pHdependent leaching and the Community Bureau of Reference(BCR)extraction were conducted at six pH values(pH=2,4,6,8,10,12)for the remediated soil treated through thermal curing.The pHdependent leaching results showed that with the formation of ZnCr2O4 spinel phases,the remediated soil exhibited strong inherent resistance to acidic attack over longer leaching periods.Furthermore,the BCR extraction results showed that the leaching agent pH value mainly affected the acid-soluble fraction content.Moreover,a strong complementary relationship was noted between the leaching and acid-soluble fraction contents,indicating that the sum of these two parameters is representative of the remediated soil risk value.Therefore,we proposed a two-step calculation method to determine the sum of the two heavy metal parameters as the risk value of remediated soil.In contrast to the traditional one-step calculation method,which only uses the leaching content as the risk value,this two-step calculation method can effectively avoid underestimating the risk of remediated soil.
